In an attempt to meet the growing demands of the personal computer (PC) consumer, PC manufacturers are constantly improving system performance. Historically, consumer demands have focused on upgrading five main aspects of the PC: processor speed and functionality, memory speed and size, power consumption, visual quality, and I/O performance. Manufacturers improve PCs through technological advances in the processes used to fabricate the integrated devices within the PC and/or through hardware or software design improvements. The PC producers often strive to implement these technological or design advances into consumer available products as soon as possible in order to keep up with consumer demands and to compete with other PC manufacturers.
Given the rapid advances in technology, a computer system can become obsolete in a relatively short amount of time. Consequently, computer owners often desire to upgrade their current systems to obtain the processing advantages of the changing computer market in the most cost effective manner. One way in which a consumers may upgrade their computer system is by replacing the printed circuit (PC) board (often referred to as the motherboard) that is housed within the computer system. The motherboard of a computer system commonly holds and interconnects the main processor device, a clock generation device and other integrated devices and components that determine the functionality of the system. However, replacing the whole motherboard as a unit tends to be a narrow upgrade path for the consumer since it is limited by the physical constraints of the box in which the motherboard resides. Commonly, future motherboards have different shapes and sizes not adaptable to previous box designs. Also, replacing the motherboard is relatively expensive and often times not a viable option to the consumer.
In addition, from the perspective of a PC manufacturer, redesigning motherboards is a time consuming process. Presently, it takes close to a year to design and implement a new motherboard. Consequently, upgrades cannot be made available to the consumer during this time and neither manufacturers nor consumers gain the benefits of the technological advances until the redesigned motherboard is ready.
Another upgrade option is implemented by replacing the current processor device residing on the motherboard, with a new upgraded processor device. In general, upgraded processors are designed to be faster and more power efficient than their predecessors due to newly developed technologies and circuit designs. As a result, the consumers can upgrade the speed of their computer system by replacing their current processor device. In addition, redesigning a processor device is more cost and time effective than redesigning a complete motherboard.
Since the upgraded processor has increased speed capability, it typically has different clocking requirements than that which are provided by the clock generation device residing on the original motherboard. Consequently, to take advantage of the new processor's increased speed, the original clock signal from the motherboard is often multiplied up to a rate at which the new processor can operate. Presently, increasing the rate of the motherboard clock is performed internally by the processor device with additional phase locked loop (PLL) circuitry.
The disadvantage of this upgrade option is that the new processor chip is designed to upgrade only that particular motherboard design. The reason for this is that the processor's I/O bus is designed to have a communication protocol that is adaptable to a particular motherboard design. Further, the PLL of the processor device is tuned to increase the clock rate for a given fixed motherboard clock rate. As a result, the consumers may be limited to which processor they can upgrade with.
Upgrading with a new processor device may also be done without adapting the clock rate of the motherboard to the new processor. However, in this case, the advantages of speed provided by the new processor are not realized and thus this upgrade option is greatly limited.
Another problem with replacing the processor device occurs in the case in which a PC manufacturer offers a range (or family) of computer systems allowing the consumers to choose within the family in order to satisfy their processing needs. Commonly, the family of processors offer different processing options. In order to provide these various options each family member has a corresponding different motherboard design adapted to a particular processor chip. Due to the fact that each family member has a different motherboard design, a processor device that can be used to upgrade one family member cannot be employed for upgrading another family member. For example, it might not be possible to upgrade a lower-end processor in the family with the same processor device as a higher-end processor. Thus, once again, a particular motherboard's upgradeability may be limited by whether an upgraded processor device is available.
What is needed is a means of upgrading a computer system without the associated time delays and cost of redesigning a motherboard and without the limitations associated with replacing the processor device on the motherboard.